CVE-2025-46734
League Commonmark Attributes Extension Cross-Site Scripting Vulnerability
Description
league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.
INFO
Published Date :
May 5, 2025, 8:15 p.m.
Last Modified :
May 5, 2025, 8:54 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
2.7
Exploitability Score :
3.1
Affected Products
The following products are affected by CVE-2025-46734
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-46734.
| URL | Resource |
|---|---|
| https://github.com/thephpleague/commonmark/commit/f0d626cf05ad3e99e6db26ebcb9091b6cd1cd89b | |
| https://github.com/thephpleague/commonmark/security/advisories/GHSA-3527-qv2q-pfvx |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-46734 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-46734 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
May. 05, 2025
Action Type Old Value New Value Added Description league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Reference https://github.com/thephpleague/commonmark/commit/f0d626cf05ad3e99e6db26ebcb9091b6cd1cd89b Added Reference https://github.com/thephpleague/commonmark/security/advisories/GHSA-3527-qv2q-pfvx
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-46734 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-46734
weaknesses.